Ignition system



Jan. 27, 1959 s. c. BAKER 2,371,413

IGNITION SYSTEM Filed Oct. 25, 1954 2 Sheets-Sheet 1 J4 l flEW/BUI'OR I 43 J6 44 g L J01 54 IN VEN TOR. fizgpew C. Zeke/ Jan. 27, 1959 Filed Oct. 25. 1954 S. C. BAKER IGNITION SYSTEM 2 Sheets-Sheet 2 United States Patent IGNITEON SYSTEM Stephen C. Baker, North Riverside, Ill.

Application October 25, 1954, Serial No. 464,293

6 laims. (Cl. 315-224) This invention is concerned generally with internal combustion engines, and more particularly with an improved spark ignition system therefor.

Spark ignited internal combustion engines generally utilise an ignition coil comprising a low voltage primary and a high voltage secondary. Direct current is applied to the primary and is interrupted by distributor points which are opened and closed, conventionally spoken of as being made and broken, by a cam driven by the engine. Obviously the time during which the contacts are closed between successive openings is dependent upon engine speed. Thus, at low speeds thereis a relatively long time for the primary current to build up as compared with the time for current build-up at high engine speeds. Thus, in the usual case the current does not build up enough at high engine speeds, and a weak spark results. If the coil is designed for proper operation at high engine speeds, then the current builds up too much at low engine speeds and the breaker points are severely burned and have a short operational life.

Accordingly, it is an object of this invention to provide an ignition coil for an internal combustion engine which maintains a substantially uniform spark over the complete operational speed range of the engine with which it is associated.

More specifically, it is an object of this invention to provide an inductance coil for use with an internal combustion engine wherein the permeability of the coil is varied so as to produce a uniform spark throughout the speed range of the engine.

Another object of this invention is to provide an auxiliary spark coil for use with a conventional spark coil in an internal combustion engine to maintain a substantially uniform spark over the speed range of the engine, specifically by varying the inductance of the auxiliary coil.

It is another object of this invention to provide an auxiliary spark coil for an internal combustion engine having a variable permeability which is automatically controlled by the speed of the engine, specifically by means of the coil current, and it is still a further object of this I invention to provide such a coil wherein the permeability remains substantially constant at any given speed, and moves smoothly in accordance with speed changes.

My invention contemplates achieving the foregoing objects through the provision of an auxiliary induction coil having a movable core urged out of the center of the coil .by a spring, the core being attracted into the coil by energization of the coil winding, and the distance which the core penetrates being dependent upon the time during which the primary circuit is made, and hence upon the current buildup in the coil. The auxiliary coil is filled with transformer oil to provide a dash-pot action preventing rapid shifting of the core back and forth at low engine speeds.

When the associated engine is operating at low speeds, the time of coil energization will be long and the core will be pulled far into the coil. Thus the permeability will be high, and current build up will be retarded. The

Patented Jan. 27, 1959 retarded current build up limits the voltage across the coil, so when my coil is connected in parallel with the primary winding of a conventional spark coil, the voltage, and hence the current, build up more slowly than normal in the spark coil. This etfect varies with the effective core permeability of my auxiliary coil, and this varies with engine speed and the dependent time during which the breaker points are closed.

When such a coil was tested, it was found that conventional breaker points were very quickly burnt up. However, I have invented improved breaker points wherein the contacts are relatively rotated from time to time in an orbital manner whereby continuously to present clean contacting surfaces. The large effective contact area gained in this manner not only eliminates the short contact life resulting from burning when used with my auxiliary coil, but actually improves the performance of the breaker points in promoting severe arcing that causes the metal eroded from one contact point to be blown away rather than allowing this metal to be deposited as a metallic oxide on the opposite contact point. Thus, it will be seen that the improved coil and the improved breaker points have particular utility when used in combination.

Accordingly, it is an object of this invention to provide the combination of ignition coil means causing severe arcing of breaker points, and breaker points which operate most satisfactorily when caused to are severely.

More specifically it is an object of this invention to utilise spark coil means of variable permeability in combination with breaker points which are relatively movable in an orbital manner to achieve a constant spark of high energy content over the entire speed range of an accompanying internal combustion engine.

Other and further objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawings, wherein:

Fig. 1 is a schematic wiring diagram of an ignition system in accordance with the principles of my invention;

Fig. 2 is a cross sectional view through the coil formi ng an important part of my invention;

Fig. 3 is a plan view of a distributor constructed in accordance with the principles of my invention with the distributor cap and rotor removed;

Fig. 4 is a vertical sectional view through the distributor;

Fig. 5 is an end view of the orbitally movable contact point; and

Fig. 6 is a sectional view thereof along the line 66 in Fig. 5.

Referring first to Fig. 1, there will be seen a complete ignition system such as might be found in an automobile, the ignition system including a battery indicated at 14) and grounded at one end. The other end of the battery is connected by means of a cable 12 to input connection 16 of an ignition or spark coil 15. This comprises the usual case (not shown) and includes primary coil 16 having one end thereof connected to the input connection 14. The other end is connected through a wire 13 to a condenser 20 which is grounded at 22. Breaker points 24 parallel the condenser 20 in accordance with the usual practice.

The spark coil 15 further includes a secondary winding 2.6 grounded as at 28 and having an output connection as at 38. The primary and secondary windings l6 and 26 are wound on a common core 32 in accordance with the usual practice, and it will be understood that the ignition coil 15 may be conventional in every respect.

The output connection 30 of the ignition coil 15 is connected by means of a high tension wire 34 to a distributor 36. This distributor will be provided with a 3 number of output connections in accordance with the number of cylinders of the accompanying engine, and one of the output connections is indicated at 38. Each output connection is connected by means of a wire 40 to a spark plug indicated schematically at 42, the spark plug being grounded as .at 44.

In accordance with the principles of my invention an auxiliary inductance coil, which might be termed an auxiliary spark or ignition coil 46 is connected in parallel with the primary winding of coil :15. Thus, one end 48 of the primary coil winding 50 of the auxiliary coil 46 is connected to the input connection 14 of the ignition coil 15. The other input connection 52 of the winding 50 is connected by means of a wire 54 to the wire 18 of the conventional ignition coil primary. The core 62 of the auxiliary coil is indicated as being variable. The core is variable in efiective permeability to attain the uniform spark desired, and the structure by means of which this is accomplished will be seen with reference to Fig. 2.

The auxiliary coil 46 includes an insulating base 64 having a generally cylindrical hollow stem 66 closed at the lower end as at 68, and provided intermediate its ends with a circumferential flange 74 A generally cylindrical shell, case, or housing 72 is associated with the flange 70 by any suitable means such as a crimped-over edge 74 of the shell. The coil winding 50 is wound about the upwardly projecting portion 76 of the stem 66, and a core 78 in the form of a cylindrical slug is pressed toward the bottom or closed end 68 of the stem by means of a coil spring 80 hearing up against the top or closed end of the shell 72. The slug or core 78 may be of any desired construction, and solid soft iron is suggested for this purpose. The ends of the winding are connected to terminals which may be-in a form of screws 82 projecting through the flange 7G. The bore through the stem 66 and upwardly projecting portion 76 thereof, and the interior of the shell 76 are filled with transformer oil as is indicated at 84. This causes a dashpt action which prevents the core or slug 78 from moving rapidly.

The effective permeability of the core of my auxiliary spark coil 46 varies automatically. Thus, when an associated engine is operating at a low speed, the circuit is completed for a relatively long time. As a result, the slug 78 is pulled far up into the upper stem portion 76 in the center of the windings and presents a high permeability. The transformer oil prevents the slug 73 from being returned to its lowermost position as illustrated under the influence of the spring 80 when the breaker points are opened to interrupt the primary circuit. if the slug were allowed to oscillate back and forth, then the permeability would vary with the movement of the slug, and considerable noise would be generated. When the associated internal combustion engine operates at high speeds, the circuit will be closed for shorter lengths of time, and the circuit current thus will tend to be weaker. As a result, the attractive force on the slug will be less and the spring 36. will hold the slug more toward the illustrated lower position. Accordingly, the permeability will be less, and the primary current will build up more rapidly than when the slug is pulled farther into the coils. The primary current of the coil cannot build up any more rapidly inasmuch as the voltages across the parallel connected coils will at all times be equal.

As a result, the primary current of the coil 15 will build up to approximately the same value regardless of the energizing period, and the ultimate spark produced will remain substantially constant in energy throughout the entire range of engine speeds.

The auxiliary coil 46 has been illustrated as incorporated in a separate and individual case. It is contemplated that the coil would be produced in this manner for addition to existing ignition circuits. However, the external form of the coil is not critical, and it is contemplated that the auxiliary coil could be incorporated into the same case with the usual existing coil, and 1t is thought that it would be preferable to supply the coil so constructed for use with new installations.

The distributor 36 is illustrated in detail in Figs. 3 and 4. This distributor comprises the usual metallic body or housing 86 of generally cylindrical configuration and having a vacuum fitting 88 on the side thereof, such vacuum fitting being connected by suitable tubing to the carburetor for advancing the spark in accordance with engine requirements. The distributor is provided with a breaker plate 90, and the upturned end $2 of an L-shaped connecting rod 94 projects through an opening in this plate, being held by means such as a pin or key 96. The rod 9-1 is connected to a diaphragm (not shown) in the vacuum fitting 38 for longitudinal movement in accordance with carburetor vacuum, whereby to rotate the plate which is rotatably mounted in conventional fashion.

The distributor 36 is provided with a distributor shaft 98 on which there is mounted a cam ltltl. The distributor herein shown is provided with a cam having eight flat sides and eight lobes for use with an eight cylinder engine.

A breaker point unit 102 is mounted on the breaker plate 90. This breaker point unit comprises a Web 104 adjustably fixed to the breaker plate 96 by means of screws 106 passing through elongated slots 1% adjacent the opposite ends of the web. A stud 110 projects up wardly from the web, and a movable breaker arm 112 is rotatably mounted on this stud, and is insulated thercfrom by an insulating sleeve 114 of fibre or the like. A spring and contact member 116 which may be of one material, or may comprise a thin sheet of copper held against a leaf spring is looped over or around the stud 111 being insulated therefrom by the sleeve 114, and has one end abutting the arm 112 as it illustrated at 118. The other end is secured to a stud 120 projecting laterally from an upturned flange 122 on the edge of the web 104, the stud and strip being insulated from the flange 122 by means of a piece of sheet insulation 124 folded over the flange. The strip 116 urges the movable breaker arm 112 in a clockwise direction as illustrated in Fig. 3.

The movable breaker arm 112 is provided with a cam follower or rubbing block 126 which conveniently may be made of fibre. A breaker or contact point 128 comprising one of the pair of points 24 previously discussed is mounted at the end of this arm and hereinafter will be referred to as the relatively movable breaker point inasmuch as it corresponds to the movable point of a conventional breaker point mechanism. Indeed, it will be understood that the distributor and breaker point mechanism as described heretofore is entirely conventional In addition to the foregoing the breaker point unit is provided with a flange 130 upstanding from an edge of the web 104 near the end thereof. This flange is provided with an opening 132 (Fig. 6) into which projects a circular part 134 of a ratchet wheel 136 having crown ratchet teeth 138. A pin 140 projects somewhat loosely through an eccentric hole 141 in the ratchet wheel 136, and also projects through a washer 142 on the opposite side of the flange 130 from the ratchet wheel. A breaker point 144 forming with the breaker point 128 the pair of points 24 is secured on the end of this pin on an outer face of the washer 142. The breaker point or contact 144 hereinafter will be referred to as the relatively fixed point or contact by analogy with conventional breaker points.

The opposite end of the pin 140 projects through a washer 146 fitting somewhat loosely in an eccentric recess 148 on the same face of the ratchet wheel as the crown teeth 138. The pin is peened over as at 150, and a spiral spring 152 is flattened out inthe recess beneath the Washer 146 to maintain the washer tightly against the peened over end portion 150 to hold the contact or breaker point 144 firmly against the washer 142 without the necessity of an unduly precise fit.

The distributor herein shown and described is of the type wherein posts 154 and 156 project upwardly from the bottom of the distributor housing through relatively large openings 158 and 160 in the breaker plate 90. Somewhat similar posts 162 and 164 are rotatably mounted by means of enlarged, eccentric bases 166 and 168 in the breaker plate. Springs 170 and 172 are respectively stretched between the posts 154 and 162, and the posts 156 and 164 for resisting the tendency of the connecting rod 94 to rotate the breaker plate.

A bell crank 174 is provided with an aperture 176 rotatably fitting about the enlarged base 168 of the post 164. The large arm 178 of the bell crank is provided with a bifurcated tip having a slot 180 receiving the post 156. The opposite arm 182 of the bell crank is provided with a pivot pin 184 on which there is pivotally mounted a hook-shaped arm 186 having an upturned tip or detent 188 urged into engagement with the ratchet teeth 138 by a hairpin spring 190 encircling the pivot pin 184 and bearing against suitable upturned stops on the bell crank arm 182 and the hook-shaped lever 186. The hook-shaped lever and upturned detent thereon form a pall co-operable with the ratchet 136. Each time the breaker plate is advanced or retarded the posts 164 and 156 move relatively, thereby rotating the bell crank. In one direction of rotation of the bell crank, the detent 188 ratchets idly over the teeth 138. This is the counterclockwise direction as shown in Fig. 3. Upon return movement the detent 188 engages one of the ratchet teeth 138 to rotate the ratchet, and thence the relatively fixed breaker point 144. As will be evident from the drawings, the breaker points are eccentric relative to one another. The rotation of the relatively fixed breaker point 144 as produced by the ratchet 136 is eccentric and hence the relatively fixed point moves orbitally about the relatively movable point. Thus, the contacting surfaces of the breaker points or contacts 24, are changed from time to time and more or less at random in accordance with the advance and retardation of the breaker plate.

A condenser 192 is mounted on the breaker plate 90 to which it is secured by a screw '194, suitable co-operating indentions as at 196 being provided to prevent twisting of the condenser about the screw, and the breaker plate preferably being provided with a rectangular opening 198 into which the condenser mounting bracket extends, further to prevent rotation about the screw. A flexible wire 200 may be held beneath the screw 194 and may be secured to the distributor housing or body by means of a screw 202 to insure a positive ground of the rotatable breaker plate. The underground lead 204 of the condenser is held on the threaded stud 120 of the breaker point unit by a nut 206 thereon. It will be understood that the lead 18 from the coil primaries would be afiixed to this stud by means of another nut, and that the relatively fixed breaker point is grounded through the breaker plate. I

The distributor 36 further is provided with a distributor cap 208 moulded of plastic or other suitable insulating material and seating in a proper shoulder 210 about the upper portion of the distributor body 86. Spring clips or the like may be used to hold the cap on the body in accordance with conventional practice. A high tension lead is connected to a center contact 212 carried by the distributor cap, and this high tension lead is from the ungrounded ends of the coil secondaries. A plurality of distributor contacts 214 of conventional construction is circumferentially and coaxially disposed about the central contact 212, and these contacts are connected externally of the distributor cap to the contacts 38 previously mentioned which lead through the wires 40 to the spark plugs 42. A rotor 216 is detachably mounted on top of the cam shaft 98 and comprises a plastic or other insulating body 218 carrying a spring contact 220 engaging the central contact 212, and a contact 222 successively passing the contacts 214 without quite engag- 6 ing them, all in accordance with the conventional prac tice.

The provision of the auxiliary coil with the variable permeability results in a spark at each plug substantially constant throughout the speed range of the associated engine. The spark is sufiiciently hot that it would burn up conventional breaker points in short order. However, the larger efiiective area produced by the eccentrically movable breaker points effectively does away with this problem. Furthermore, since there is not a concentrated deposit of metallic oxide with the movable breaker points as there is in conventional fixed breaker points the initial gap can be set much more closely. The smaller gap helps to attain a much hotter spark, which combined with the constant energy content of the spark as provided by the auxiliary coil produces vastly improved engine performance at all speeds. Furthermore, it has been found by test that the arcing between the contact points when used with the auxiliary coil is so severe that most of the metal eroded from one contact point is blown away by the force of the arc, and consequently is not deposited on the opposite contact point. Thus, the movable contact point 128 gradually burns away without any corresponding build-up on the relatively fixed contact point 144. At the same time the cam follower or rubber block 126 wears down. The rate of erosion of the contact point and wear of the cam follower is so correlated that the dwell has been found to be constant throughout 10,000 miles of operation, thus requiring no adjustment whatsoever of the contact points for at least 10,000 miles. In this respect it will be noted that for best results with conventional breaker points the gap should be reset every 1,000 miles or less. By way of illustration, the gap in this combination may be set at .005 inch or less as compared with the .025 or more generally found with conventional breaker points.

Various changes in structure will no doubt occur to those skilled in the art, but since the accompanying drawings and descriptive manner are but an illustrative embodiment of the invention, it will be understood that such variations form a part of my invention insofar as they fall within the spirit and scope of the appended claims.

I claim:

1. In an internal combustion engine having a spark ignition system, the combination comprising a distributor having a shaft rotated by said engine at a speed proportional to the speed of the engine, said distributor further having a set of breaker points, one of said breaker points being orbitally movable about the other, means for orbitally moving said one breaker point from time to time, an ignition coil connected to said distributor including said breaker points and having a D. C. primary circuit opened by said breaker points from time to time, and an auxiliary coil connected to saiddistributor in circuit with said ignition coil, said auxiliary coil having a movable core part with a rest position and having a predetermined range of movement for varying the permeability thereof, said movable core part being moved a proportional part of said range in accordance with engine speed to produce a constant spark throughout a wide range of engine speeds.

2. In an internal combustion engine having a spark ignition system, the combination comprising a distributor driven from said engine and having a set of breaker points, one of said breaker points being orbitally movable about the other and the contacts being movable into and out of engagement with one another, means for orbitally moving said one breaker point, ignition coil means connected to said distributor including said breaker points, said ignition coil means comprising a movable core part with a rest position and having a predetermined range of movement for varying the permeability of said coil means, and means operatively interconnecting said distributor and said movable core part and moving said movable core part a proportional part of said range in accordance with engine speed to produce a substantially constant spark over a wide range of engine speeds.

3. In an internal combustion engine having a spark ignition system, the combination comprising a distributor mounted on said engine and having a set of breaker points movable into and out of engagement with one another and means driven by said engine for so moving said breaker points in timed relation therewith, one of said breaker points being orbitally movable about the other, and means for'orbit-ally moving said one breaker point, and ignition coil means connected to said distributor including said breaker points, said ignition coil means comprising winding means and a core of magnetic material, said winding means being alternately energized and open circuited by said breaker points, said core being movable relative to said winding means and moving in accordance with the magnetic force of said winding means as said magnetic force varies with the speed of energizing and open circuiting said winding means to vary the efiective permeability of the core in accordance with engine speed to produce a substantially constant spark over a wide range of engine speeds.

4. An ignition system as set forth in claim 3 wherein said ignition coil means further includes means preventingr at having a set of breaker points relatively movable into and out of contact with one another and means driven by said engine for so moving said points, one of said breaker points being orbitally movable about the other, means for orbitally moving said one breaker point, and ignition coil means connected to said distributor including said breaker points, said ignition coil means comprising a housing having a tubular central portion, a winding encircling said tubular central portion With said tubular central portion extending axially beyond said winding, said winding being alternately open circuited and energized through said breaker points, a core comprising a magnetic slug axially movable in said tubular central portion in accordance ith the magnetic force of said winding as the magnitude of said force varies with the speed of said engine and consequent rapidity of movement of said break- I er points into and out of contact, spring means in said tubular central portion urging said slug axially outwardly of said winding, and a liquid medium in said housing including said tubular portion preventing unduly rapid movement of said slug.

References Cited in the file of this patent UNITED STATES PATENTS l,l99,936 Simon Oct. 3, 1916 2,313,989 Caldwell et al Mar. 16, 1943 2,389,637 Ruben Nov. 27, 1945 2,389,638 Ruben Nov. 27, 1945 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,871,413 January 2'7, 1959 Stephen Ga Baker It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 34, for "as it" read is it column 5, line 42 for "indentions" read indentations line 50, for "underground." read ungrounded Signed and sealed this 30th day of June 1959 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Ofiicer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,871,413

Stephen 00 Baker It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

"as it" read be is it e-olunm 5, line 42,v

Column 4, line 34, for tations line 5C), for "underground" read for "indentions" read inden ungrounded Signed and sealed this 30th day of June 1959.,

(SEAL) Attest:

KARL H. AXLINE' Attesting Oflicer ROBERT C. WATSON Commissioner of Patents January 27, 1959 v 

